mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-11-19 09:44:30 +01:00
45 lines
1.0 KiB
Perl
45 lines
1.0 KiB
Perl
;# Usage: &look(*FILEHANDLE,$key,$dict,$fold)
|
|
|
|
;# Sets file position in FILEHANDLE to be first line greater than or equal
|
|
;# (stringwise) to $key. Pass flags for dictionary order and case folding.
|
|
|
|
sub look {
|
|
local(*FH,$key,$dict,$fold) = @_;
|
|
local($max,$min,$mid,$_);
|
|
local($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
|
|
$blksize,$blocks) = stat(FH);
|
|
$blksize = 8192 unless $blksize;
|
|
$key =~ s/[^\w\s]//g if $dict;
|
|
$key =~ y/A-Z/a-z/ if $fold;
|
|
$max = int($size / $blksize);
|
|
while ($max - $min > 1) {
|
|
$mid = int(($max + $min) / 2);
|
|
seek(FH,$mid * $blksize,0);
|
|
$_ = <FH> if $mid; # probably a partial line
|
|
$_ = <FH>;
|
|
chop;
|
|
s/[^\w\s]//g if $dict;
|
|
y/A-Z/a-z/ if $fold;
|
|
if ($_ lt $key) {
|
|
$min = $mid;
|
|
}
|
|
else {
|
|
$max = $mid;
|
|
}
|
|
}
|
|
$min *= $blksize;
|
|
seek(FH,$min,0);
|
|
<FH> if $min;
|
|
while (<FH>) {
|
|
chop;
|
|
s/[^\w\s]//g if $dict;
|
|
y/A-Z/a-z/ if $fold;
|
|
last if $_ ge $key;
|
|
$min = tell(FH);
|
|
}
|
|
seek(FH,$min,0);
|
|
$min;
|
|
}
|
|
|
|
1;
|